Current steering wheel designs may include one or more sensor mats around a rim of the steering wheel frame that are configured for detecting the presence of a driver's hand using capacitive-type sensing. Known sensor mats include a wire loop that is sewn to a fabric or foam substrate.
The steering wheel frame is typically made of metal, such as a magnesium alloy or steel and can be a source of interference for the signal(s) in the sensing mat.
Thus, existing sensor mats may be time consuming to manufacture, which includes designing a wire stitch layout for the sensor and designing the wire stitch layout for the shield, each being on separate mats that must fit correctly over the complex curve shape of the steering wheel rim. In addition, the pattern may need to be redesigned depending on which areas should provide sensing and the vehicle manufacturer's steering wheel specifications, which can be time consuming. Furthermore, the manufacturing process and available materials limits the ability to use the available space on the base substrate.
Accordingly, there is a need in the art for an improved sensor mat and method for making the same.